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Properties of Minerals

Vocabulary

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mineral: a naturally occurring, inorganic rock that has a crystal and a definite chemical composition
crystal: a solid in which he atoms are arranged in a pattern that repeats again and again
element: a substance composed of a single kind of atom
compound: two or more elements are combined so that the elements no longer have distinct properties
Mohs hardness scale: this scale places ten minerals from softest to hardest
streak: a mineral's pigment of it's powder
luster: the state or quality of shining by reflecting light from it's surface
cleavage: a mineral that opens easily along flat surfaces
fracture: describes how a mineral looks when it breaks
fluorescence: a property minerals have (if they glow under ultra-violet light it shows it has that)

Outline

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What is a mineral?

• a mineral must have these things to be a mineral
  • Naturally occuring
    • Has to have accured naturally without people trying to make something with the substances
      • Some substances that haven't occured naturally that we use are Cement, brick, Steel, and Glass even though these substances come from the Earth's crust they were man made so they don't count as minerals
  • Inorganic
    • Has to not been made in the Earth's crust but were once part of a living thing ...
      • ...As in coal, which formed naturally in the Earth's crust but it comes from the remains or plants and animals from at leat a million years ago
  • Solid
    • Has to be a solid which has a definite size and shape
      • Here are some solids : rocks, tables and chairs are all solids.
        • Liquids aren't solids : water, soda, and milk
        • Neither are Gas : laughing gas other gases
  • Crystal Structure
    • The particles in that mineral's line up has a pattern that repeates itself on and on again.
      • There are different shapes and sizes for crystal structure
        • There is a cube, and triangular one, and other shapes
  • Definite Chemical Composition
    • Which means the mineral always contains the elements it has in definite proportions

• Identifying Minerals

  • Hardness
    • Mohs Hardness Scale
  • Color
    • use of eye
  • Streak
    • Against steak plate
  • Luster
    • Light
  • Density
    • Look how big or feel their weight
  • Crystal Systems
    • First cuts a think sliver of the rock then looks under a microscope to see the crystals
      • They cut it so small so they can use the light to actually see the crystals clear
  • Cleavage and Fracture
    • The way a mineral breaks in an irregular what or a mineral that has split ends
  • Special Properties
    • including fluorescence

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